The outbreak was confirmed at a farm in Jagang province in North Korea near the country's border with China on May 25, South Korea's Ministry of Agriculture, Food and Rural Affairs said in a statement. More than 20 hogs were culled and more than 70 pigs died from the virus, the ministry said.
The highly contagious disease, which is fatal to pigs but does not affect humans, has spread rapidly across China since it was first detected in the country last August and has also been reported in Vietnam. There is no vaccine against it.
The South Korean government held a meeting on Friday to discuss ways to prevent the spread of the virus. Measures will include stepping up disinfection near the border areas between the two Koreas, the ministry said.
"Although the outbreak occurred in Jagang near North Korea's border with China, there is a possibility that the virus could spread to the South and we plan to carry out extra disinfection measures," Oh Soon-min, director general of the agriculture ministry said at a press briefing.
Separately, South Korea's unification ministry said it would communicate with North Korea through an inter-Korean liaison office to work on detailed protection measures.
Pork is a popular meat among South Koreans and is cheaper than beef. The country had about 12 million pigs in the first quarter of the year, according to data from Statistics Korea.
North Korea has not confirmed the swine fever outbreak, but the state-run Rodong Sinmun newspaper on Friday reported three articles about the risks of the virus and how rapidly it is spreading around the world.
However, South Korea's agriculture ministry said North Korea had reported the outbreak to the Paris-based World Organisation for Animal Health (OIE) on Thursday, and has taken measures to prevent its spread, including disinfection.
Outbreaks of bird flu and foot-and-mouth disease have been reported in North Korea in the past but the size of North Korea's poultry and livestock population is not known.
The South's agriculture ministry estimated that North Korea has about 6.6 million of pigs at 14 farms, Oh told the press briefing.
Shares of South Korean animal medicine suppliers, Eagle Veterinary Technology and Cheil Bio rallied on Friday as much as 23% and 16%, respectively, while those of animal feed maker, Woosung Feed jumped more than 12%.